1. Field of Invention
This invention relates to an automatic positioning mechanism for automatically moving the working head of a machine tool or other similar device through a pre-programmed pattern of movement.
More particularly, the invention relates to such an automatic positioning mechanism which is simple in design, relatively low cost, reliable in operation and easy to maintain; and which employs simple mechanical disc-type control-drive cams both to control the pattern of movement and to drive the apparatus.
2. Background Problem
There are a number of known mechanisms driven by mechanical cams to generate a variety of shapes in space. One of these known mechanisms is described in U.S. Pat. No. 3,818,769 issued June 25, 1974 for an "Apparatus for Repeated Tracing Various Patterns". All of the known mechanisms of this type are designed for limited performance to do simple point to point patterns of motion and/or are limited in size and amount of detail that can be generated per operating cycle of the mechanism. Recent developments in the automotive industry for dispensing a mastic-like material as a formed-in-place gasket on automotive parts, and on other similar products, has caused the need for simple mechanisms of this same general type but with much more capability than that possessed by the known prior art mechanisms. To satisfy this last mentioned need, the range of motion must be large, the shape must be accurate in details of intricate shapes and it must be extremely reliable. There are basic inherent shortcomings in generating patterns of motion with a mechanically driven cam technique. The size of the follower and the size of the cam greatly influences the amount of detail that can be included in the shape of contour of the cam patterns. To satisfy this need the present invention was developed.